go

Getting "bytes.Buffer does not implement io.Writer" error message

I'm trying to have some Go object implement io.Writer, but writes to a string instead of a file or file-like object. I thought bytes.Buffer would work since it implements Write(p []byte). However when I try this:

import "bufio"
import "bytes"

func main() {
    var b bytes.Buffer
    foo := bufio.NewWriter(b)
}

I get the following error:

cannot use b (type bytes.Buffer) as type io.Writer in function argument:
bytes.Buffer does not implement io.Writer (Write method has pointer receiver)

I am confused, since it clearly implements the interface. How do I resolve this error?

Solution

  • Pass a pointer to the buffer, instead of the buffer itself:

    import "bufio"
import "bytes"

func main() {
    var b bytes.Buffer
    foo := bufio.NewWriter(&b)
}